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我有一个关于聚合然后再次发散的多条路径的问题。然后，一些聚合应该只考虑路径的一个子集，而其他聚合则更多。

我将使用产品制造示例尽可能地解释这一点。假设我有一家公司生产一种由供应商提供的由某种材料组成的产品。更具体地说，这家公司生产一种产品类型的 5 件产品，由 10 克一种材料组成。因此，在制造过程中，他们使用了 50 克这种材料。但是在生产中存在材料浪费，他们实际上使用了70克，浪费了20克。

我想计算的是每种产品和供应商的材料校正重量，考虑到浪费。在这种情况下，这很容易。70克

简单制作

当这变得更复杂时会发生什么： 复杂的生产

现在，每个产品 1 和供应商 1 的材料 1 的校正重量为 58.82 克。这是公式：

material composition = sum(production amount * product composition)
corrected weight = (production amount * product composition * 
                     (purchased / (material composition)))

IE

material composition = (5 * 10) + (20 * 40) = 850
corrected weight = (5 * 10 * (1000 / (850))) = 58.82

因此，对这个示例运行密码查询应该会给我 6 个结果，因为这是产品、材料和供应商的排列数量。

问题是，如何编写这样的查询。我尝试过reduce函数，重复with's等，但它似乎总是聚集在错误的节点集上......

为了完整起见，这里是生成图表的密码：

创造：

create (c:Company {name:'test', id:'c1'}),  
       (p1:Product {name:'product1', id:'p1'}),  
       (p2:Product {name:'product2', id:'p2'}), 
       (m1:Material {name:'material1', id:'m1'}), 
       (m2:Material {name:'material2', id:'m2'}), 
       (s1:Supplier {name:'supplier1', id:'s1'}), 
       (s2:Supplier {name:'supplier2', id:'s2'}), 
       (s3:Supplier {name:'supplier3', id:'s3'})

相对：

match (c:Company {id:'c1'}), 
    (p1:Product {id:'p1'}), 
    (m1:Material {id:'m1'})
    merge (c)<-[pb_r1:PRODUCED_BY {amount:5}]-(p1)-[co_r11:CONSISTS_OF {amount:10}]->(m1)
    with c, p1, m1
    match (p2:Product {id:'p2'})
    merge (c)<-[pb_r2:PRODUCED_BY {amount:20}]-(p2)-[co_r12:CONSISTS_OF {amount:40}]->(m1)
    with p1, p2, m1
    match (s1:Supplier {id:'s1'})
    merge (m1)-[pf_r1:PURCHASED_FROM {amount: 1000}]->(s1)
    with p1, p2
    match (m2:Material {id:'m2'})
    merge (p1)-[co_r21:CONSISTS_OF {amount:30}]->(m2)
    with p2, m2
    merge (p2)-[co_r22:CONSISTS_OF {amount:80}]->(m2)
    with m2
    match (s2:Supplier {id:'s2'})
    merge (m2)-[pf_r2:PURCHASED_FROM {amount: 1000}]->(s2)
    with m2
    match (s3:Supplier {id:'s3'})
    merge (m2)-[pf_r3:PURCHASED_FROM {amount: 1000}]->(s3)
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1 回答 1

1 
// Selection of the supply chain and production by Company 
//
MATCH (C:Company {id:'c1'})
        <-[pb:PRODUCED_BY]-
      (P:Product)
        -[co:CONSISTS_OF]->
      (M:Material)
        -[pf:PURCHASED_FROM]->
      (S:Supplier)

// Grouping by materials, calculation material composition,
// and the preservation of the chain to the supplier
// 
WITH M,
     S, // group by supplier 
     SUM(pb.amount*co.amount) as mComp, 
     collect({
       product:P,
       prod: pb.amount, 
       comp: co.amount, 
       purchased: pf.amount
     }) as tmps

// Calculating the correct weight by material and supplier
// 
UNWIND tmps as tmp
RETURN M as material, 
       tmp['product'] as product, 
       S as supplier,
       1.0 * tmp['prod'] * tmp['comp'] * tmp['purchased'] / mComp as cWeight
于 2016-05-15T14:48:39.530 回答